Abstract: The dynamic propagation of subsurface cracks on the inner ring of rolling bearings can affect the stability of bearing operation, thereby affect the remaining service life. To address this issue, the influence laws of initial subsurface cracks with different curvatures on the stress distribution and crack propagation were investigated for the inner ring of rolling bearings. Firstly, based on the extended finite element method, a model of a cylindrical roller bearing subjected to radial load was constructed. Then, based on the morphological characteristics of the subsurface cracks of the rolling bearing, the dynamic propagation process of the initial cracks with different curvatures on the subsurface of the inner raceway was simulated. Finally, based on the simulation results, the variation of the subsurface crack tip stress with the crack curvature and the influence of the crack tip stress on the crack propagation were analyzed and discussed under the same working conditions. The research results show that stress concentration occurs at the tip of subsurface crack under radial load. The crack propagation is mainly affected by the horizontal stress (S11). Under the same working conditions, the subsurface cracks in the curvature range of 0.25 mm-1~1.67 mm-1, the crack ends stress of larger curvature is smaller. The larger the curvature of the subsurface crack is, the smaller the crack propagation length and angle are. By comparing the propagation length and propagation angle of subsurface cracks, it is found that the subsurface cracks with larger curvature have less influence on the damage degree and life of the bearing. These results provide a theoretical basis and reference for better understanding and preventing bearing damage.
Key words:  cylindrical roller bearing; remaining service life; initial subsurface crack; stress distribution; dynamic crack growth; different curvature; extended finite element method(XFEM)